Re: [PATCH v8 03/10] target/ppc: PMU: update counters on PMCs r/w

[David Gibson]

On Thu, Nov 25, 2021 at 12:08:10PM -0300, Daniel Henrique Barboza wrote:
> Calling pmu_update_cycles() on every PMC read/write operation ensures
> that the values being fetched are up to date with the current PMU state.
> 
> In theory we can get away by just trapping PMCs reads, but we're going
> to trap PMC writes to deal with counter overflow logic later on.  Let's
> put the required wiring for that and make our lives a bit easier in the
> next patches.
> 
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  target/ppc/cpu_init.c            | 12 ++++++------
>  target/ppc/helper.h              |  2 ++
>  target/ppc/power8-pmu-regs.c.inc | 29 +++++++++++++++++++++++++++--
>  target/ppc/power8-pmu.c          | 14 ++++++++++++++
>  target/ppc/spr_tcg.h             |  2 ++
>  5 files changed, 51 insertions(+), 8 deletions(-)
> 
> diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
> index e0b6fe4057..a7f47ec322 100644
> --- a/target/ppc/cpu_init.c
> +++ b/target/ppc/cpu_init.c
> @@ -6833,27 +6833,27 @@ static void register_book3s_pmu_sup_sprs(CPUPPCState 
> *env)
>                       KVM_REG_PPC_MMCRA, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_PMC1, "PMC1",
>                       SPR_NOACCESS, SPR_NOACCESS,
> -                     &spr_read_generic, &spr_write_generic,
> +                     &spr_read_PMC, &spr_write_PMC,
>                       KVM_REG_PPC_PMC1, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_PMC2, "PMC2",
>                       SPR_NOACCESS, SPR_NOACCESS,
> -                     &spr_read_generic, &spr_write_generic,
> +                     &spr_read_PMC, &spr_write_PMC,
>                       KVM_REG_PPC_PMC2, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_PMC3, "PMC3",
>                       SPR_NOACCESS, SPR_NOACCESS,
> -                     &spr_read_generic, &spr_write_generic,
> +                     &spr_read_PMC, &spr_write_PMC,
>                       KVM_REG_PPC_PMC3, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_PMC4, "PMC4",
>                       SPR_NOACCESS, SPR_NOACCESS,
> -                     &spr_read_generic, &spr_write_generic,
> +                     &spr_read_PMC, &spr_write_PMC,
>                       KVM_REG_PPC_PMC4, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_PMC5, "PMC5",
>                       SPR_NOACCESS, SPR_NOACCESS,
> -                     &spr_read_generic, &spr_write_generic,
> +                     &spr_read_PMC, &spr_write_PMC,
>                       KVM_REG_PPC_PMC5, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_PMC6, "PMC6",
>                       SPR_NOACCESS, SPR_NOACCESS,
> -                     &spr_read_generic, &spr_write_generic,
> +                     &spr_read_PMC, &spr_write_PMC,
>                       KVM_REG_PPC_PMC6, 0x00000000);
>      spr_register_kvm(env, SPR_POWER_SIAR, "SIAR",
>                       SPR_NOACCESS, SPR_NOACCESS,
> diff --git a/target/ppc/helper.h b/target/ppc/helper.h
> index ea60a7493c..d7567f75b4 100644
> --- a/target/ppc/helper.h
> +++ b/target/ppc/helper.h
> @@ -21,6 +21,8 @@ DEF_HELPER_1(hrfid, void, env)
>  DEF_HELPER_2(store_lpcr, void, env, tl)
>  DEF_HELPER_2(store_pcr, void, env, tl)
>  DEF_HELPER_2(store_mmcr0, void, env, tl)
> +DEF_HELPER_3(store_pmc, void, env, i32, i64)
> +DEF_HELPER_2(read_pmc, tl, env, i32)
>  #endif
>  DEF_HELPER_1(check_tlb_flush_local, void, env)
>  DEF_HELPER_1(check_tlb_flush_global, void, env)
> diff --git a/target/ppc/power8-pmu-regs.c.inc 
> b/target/ppc/power8-pmu-regs.c.inc
> index fbb8977641..f0c9cc343b 100644
> --- a/target/ppc/power8-pmu-regs.c.inc
> +++ b/target/ppc/power8-pmu-regs.c.inc
> @@ -181,13 +181,23 @@ void spr_write_MMCR2_ureg(DisasContext *ctx, int sprn, 
> int gprn)
>      tcg_temp_free(masked_gprn);
>  }
>  
> +void spr_read_PMC(DisasContext *ctx, int gprn, int sprn)
> +{
> +    TCGv_i32 t_sprn = tcg_const_i32(sprn);
> +
> +    gen_icount_io_start(ctx);
> +    gen_helper_read_pmc(cpu_gpr[gprn], cpu_env, t_sprn);
> +
> +    tcg_temp_free_i32(t_sprn);
> +}
> +
>  void spr_read_PMC14_ureg(DisasContext *ctx, int gprn, int sprn)
>  {
>      if (!spr_groupA_read_allowed(ctx)) {
>          return;
>      }
>  
> -    spr_read_ureg(ctx, gprn, sprn);
> +    spr_read_PMC(ctx, gprn, sprn + 0x10);
>  }
>  
>  void spr_read_PMC56_ureg(DisasContext *ctx, int gprn, int sprn)
> @@ -206,13 +216,23 @@ void spr_read_PMC56_ureg(DisasContext *ctx, int gprn, 
> int sprn)
>      spr_read_PMC14_ureg(ctx, gprn, sprn);
>  }
>  
> +void spr_write_PMC(DisasContext *ctx, int sprn, int gprn)
> +{
> +    TCGv_i32 t_sprn = tcg_const_i32(sprn);
> +
> +    gen_icount_io_start(ctx);
> +    gen_helper_store_pmc(cpu_env, t_sprn, cpu_gpr[gprn]);
> +
> +    tcg_temp_free_i32(t_sprn);
> +}
> +
>  void spr_write_PMC14_ureg(DisasContext *ctx, int sprn, int gprn)
>  {
>      if (!spr_groupA_write_allowed(ctx)) {
>          return;
>      }
>  
> -    spr_write_ureg(ctx, sprn, gprn);
> +    spr_write_PMC(ctx, sprn + 0x10, gprn);
>  }
>  
>  void spr_write_PMC56_ureg(DisasContext *ctx, int sprn, int gprn)
> @@ -280,4 +300,9 @@ void spr_write_MMCR0(DisasContext *ctx, int sprn, int 
> gprn)
>  {
>      spr_write_generic(ctx, sprn, gprn);
>  }
> +
> +void spr_write_PMC(DisasContext *ctx, int sprn, int gprn)
> +{
> +    spr_write_generic(ctx, sprn, gprn);
> +}
>  #endif /* defined(TARGET_PPC64) && !defined(CONFIG_USER_ONLY) */
> diff --git a/target/ppc/power8-pmu.c b/target/ppc/power8-pmu.c
> index 47932ded4f..5f2623aa25 100644
> --- a/target/ppc/power8-pmu.c
> +++ b/target/ppc/power8-pmu.c
> @@ -145,6 +145,20 @@ void helper_store_mmcr0(CPUPPCState *env, target_ulong 
> value)
>      }
>  }
>  
> +target_ulong helper_read_pmc(CPUPPCState *env, uint32_t sprn)
> +{
> +    pmu_update_cycles(env);
> +
> +    return env->spr[sprn];
> +}
> +
> +void helper_store_pmc(CPUPPCState *env, uint32_t sprn, uint64_t value)
> +{
> +    pmu_update_cycles(env);
> +
> +    env->spr[sprn] = value;
> +}
> +
>  static void fire_PMC_interrupt(PowerPCCPU *cpu)
>  {
>      CPUPPCState *env = &cpu->env;
> diff --git a/target/ppc/spr_tcg.h b/target/ppc/spr_tcg.h
> index eb1d0c2bf0..1e79a0522a 100644
> --- a/target/ppc/spr_tcg.h
> +++ b/target/ppc/spr_tcg.h
> @@ -26,6 +26,7 @@ void spr_noaccess(DisasContext *ctx, int gprn, int sprn);
>  void spr_read_generic(DisasContext *ctx, int gprn, int sprn);
>  void spr_write_generic(DisasContext *ctx, int sprn, int gprn);
>  void spr_write_MMCR0(DisasContext *ctx, int sprn, int gprn);
> +void spr_write_PMC(DisasContext *ctx, int sprn, int gprn);
>  void spr_read_xer(DisasContext *ctx, int gprn, int sprn);
>  void spr_write_xer(DisasContext *ctx, int sprn, int gprn);
>  void spr_read_lr(DisasContext *ctx, int gprn, int sprn);
> @@ -35,6 +36,7 @@ void spr_write_ctr(DisasContext *ctx, int sprn, int gprn);
>  void spr_read_ureg(DisasContext *ctx, int gprn, int sprn);
>  void spr_read_MMCR0_ureg(DisasContext *ctx, int gprn, int sprn);
>  void spr_read_MMCR2_ureg(DisasContext *ctx, int gprn, int sprn);
> +void spr_read_PMC(DisasContext *ctx, int gprn, int sprn);
>  void spr_read_PMC14_ureg(DisasContext *ctx, int gprn, int sprn);
>  void spr_read_PMC56_ureg(DisasContext *ctx, int gprn, int sprn);
>  void spr_read_tbl(DisasContext *ctx, int gprn, int sprn);

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

signature.asc
Description: PGP signature